<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>选择器的练习</title>
  <style type="text/css">
    .red{color: red;}
    .green{color: green;}
    .font22{font-size: 22px;}
    #font24{font-size: 24px;}
    #color{color: yellow;}
    p{
      font-family: 楷体;
      text-decoration: underline;
    }
    *{
        margin: 0;
        padding: 0;
    }
  </style>
</head>
<body>
<h2 class="red">二级文本</h2>
<p class="green font22">段落一文本</p>
<p class="red font22">段落二文本</p>
<p id="color">段落三文本</p>
</body>
</html>